HWD2119 Datasheet, PDF (12/21 Pages) List of Unclassifed Manufacturers – 350mWAudio Power Amplifier with Shutdown Mode

Application Information (Continued)
HIGHER GAIN AUDIO AMPLIFIER
Figure 2
The HWD2119 is unity-gain stable and requires no external
components besides gain-setting resistors, an input coupling
capacitor, and proper supply bypassing in the typical appli-
cation. However, if a closed-loop differential gain of greater
than 10 is required, a feedback capacitor (C₄) may be
needed as shown in Figure 2 to bandwidth limit the amplifier.
This feedback capacitor creates a low pass filter that elimi-
nates possible high frequency oscillations. Care should be
taken when calculating the -3dB frequency in that an incor-
rect combination of R₃ and C₄ will cause rolloff before
20kHz. A typical combination of feedback resistor and ca-
pacitor that will not produce audio band high frequency rolloff
is R₃ = 20kΩ and C₄ = 25pF. These components result in a
-3dB point of approximately 320 kHz. It is not recommended
that the feedback resistor and capacitor be used to imple-
ment a band limiting filter below 100kHz.
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